1. Field of the Invention
The present invention relates to a LAN antenna having a directivity in a specific direction, and a reflector therefor.
2. Related Art
In view of this, Japanese Unexamined Patent Publication (KOKAI) No. 6-350334 discloses the technique in which a reflecting element is subjected to an arcuate motion on an axis of an antenna element so as to provide the directivity in a specific direction.
Furthermore, Japanese Unexamined Patent Publication (KOKAI) No. 10-502220 discloses the configuration in which a plurality of monopole antenna elements uniformly spaced on the circumference are electrically operated so as to achieve an optimum directivity.
If the above-described non-directivity antenna is used in the case where a plurality of access points exist in a wide area, there arises a problem of the interference between the access points or a problem of which point a terminal located between the access points should access to.
In spite of the use of the directivity antenna by the technique disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 6-350334 or Japanese Unexamined Patent Publication (KOKAI) No. 10-502220, the possibility of achievement of an antenna radiation pattern capable of satisfying a demand is not sufficient. Therefore, a desired gain, beam width or side lobe characteristics may not be obtained according to the radiation pattern from the above-mentioned antennas so that the above-described problems cannot be solved. Additionally, a throughput cannot be enhanced in many cases.
In these cases, if the antenna radiation directivity, that is, the beam shape, beamwidth, side lobe characteristics, gain or the like can be readily changed or adjusted in the antenna on a terminal side, and further, the pattern of a beam radiated from the antenna can be adjusted irrespectively of an elevation angle direction or a bearing direction, the interference in the above-described situation can be alleviated and the throughput can be improved. The technique disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 6-350334 or Japanese Unexamined Patent Publication (KOKAI) No. 10-502220 does not at all suggest, in particular, the adjustment of the elevation angle direction of the radiation pattern, and thus, cannot solve the above-described problems.
The present invention has been accomplished in view of the above-described problems. An object of the present invention is to provide a LAN antenna in which an interference or the like can be alleviated and a throughput can be improved, and a reflector therefor.
To obtain the above object, the present invention basically adopts the following technical constitution.
The first aspect of the present invention is a LAN antenna having a directivity comprising: a base table a projection member for enclosing an antenna element which projects from the base table a cylindrical member having a through hole, in which the projection member is fitted; and a reflector disposed on a side surface of the cylindrical member.
The second aspect of the present invention is a LAN antenna having a directivity comprising: a base table a projection member for enclosing an antenna element which projects from the base table; a cylindrical member having a through hole, in which the projection member is fitted; and a reflector disposed on a side surface of the cylindrical member wherein the cylindrical member is detachably fitted to the projection member.
In the third aspect of the present invention, the reflector comprising one or more flat plates and/or curved plates.
In the fourth aspect of the present invention, the reflector is disposed in such a manner that a reflecting surface of the reflector approaches a center thereof as the reflector goes to a bottom surface of the reflector.
In the fifth aspect of the present invention, the reflector is disposed in such a manner that a reflecting surface of the reflector approaches a center thereof as the reflector goes to a top surface of the reflector.
In the sixth aspect of the present invention, a reflecting surface of the reflector has a W-shape in a horizontal or vertical cross section.
In the seventh aspect of the present invention, a reflecting surface of the reflector has a V-shape in a horizontal or vertical cross section.
In the eighth aspect of the present invention, a reflecting surface of the reflector has a parabolic curve in a vertical or horizontal cross section.
In the ninth aspect of the present invention, the reflector is a parabolic reflector.